RP temperature changes

Question 1

equipment

Answer 1

-hydrochloric acid
-sodium hydroxide solution
-polystyrene cup and lid
-thermometer
-beaker
-measuring cylinder

Question 2

method

Answer 2

1. measure 25cm³ hydrochloric acid into a polystyrene cup
2. place the cup into a breaker for stability
3. record temperature of the hydrochloric acid
4. add 5cm³ sodium hydroxide to the cup
5. quickly place the lid on and stir using thermometer through the hole of lid
6. when the temperature stops changing, record the highest temperature reached
7. repeat and add 5cm³ sodium hydroxide until 40cm³ has been added in total

Question 3

safety

Answer 3

-wear googles, acids are irritants

Question 4

type of reaction, how can you tell

Answer 4

exothermic-temperature increase as heat is given to surroundings

Question 5

why is a polystyrene cup used?

Answer 5

to reduce the amount of heat lost

Question 6

why is important to stir the mixture?

Answer 6

to ensure the temperature measured is consistent
ensure reactants have fully reacted

Question 7

how could the temperature be measured more precisely?

Answer 7

use a digital thermometer

Question 8

how could the temperature be measured more reliably?

Answer 8

repeat and calculate a mean

Question 9

variables

Answer 9

independent-volume of NaOH
dependent-temperature change
control-volume of acid

Question 10

why is cotton wool sometimes added to surround the beaker?

Answer 10

to give more insulation